Recently, utility of drug delivery systems using a liposome has been spotlighted. Thus, many attentions have been given to studies about preparation of more effective lipid-based nanocarriers through combination of various lipid components. Particularly, active studies have been conducted to provide a liposome formed from various components so that physiologically active ingredients incorporated into the inner phase of a liposome may be delivered to cells in vivo with high efficiency to realize their maximized efficiencies.
For example, some studies have been conducted about a liposome designed in such a manner that physiologically active ingredients incorporated into a liposome are released into cells through a decrease in liposome stability caused by the specific environment of a minute organ in cells. In addition, various systems capable of drug release at a predetermined temperature or pH range have been studied by using pH- or temperature-sensitive lipids or polymers in combination.
A liposome may include various types of lipid molecules but ensures no physical stability. Thus, many studies have been conducted to ensure liposome stability. In some technologies, a specific anionic surfactant is added to a liposome to induce an increase in stability. In other technologies, static charge lipids are added or sterols, anionic lipids or sphingolipids are introduced to elements forming a liposome. Further, it has been suggested that a liposome is mixed with an aqueous phase in which a polymeric emulsifier is dissolved, or a liposome is added to lamellar liquid crystals to stabilize physiologically active ingredients.
As mentioned above, active studies have been conducted continuously to improve the stability of a liposome or emulsion. However, the technologies according to the related art cannot provide sufficient physical stability, and thus are limited in use in the fields of food, cosmetics and pharmaceuticals.
In general, it is known that a liposome based on lipid-cholesterol does not ensure long-term stability in an aqueous phase. Particularly, such a liposome is highly liable to various salts used in vivo. To allow the use of such a liposome in cosmetics and skin application products, its stability in a formulation is required. However, such a liposome easily loses its structural integrity due to various surfactants present in a formulation.